Follow a worked example.
Every example below can be loaded using its calculator’s Reset example button. Inputs use centimetres, square centimetres or cubic centimetres as labelled, while angles use degrees.
Two perpendicular legs
Given: Leg a = 3; Leg b = 4.
c = √(a²+b²); A = ab/2
| Measurement | Calculated value |
|---|---|
| Hypotenuse | 5 cm |
| Area | 6 cm² |
| Perimeter | 12 cm |
| Angle opposite leg a | 36.869898° |
Hypotenuse and one leg
Given: Hypotenuse c = 5; Leg a = 3.
b = √(c²−a²)
| Measurement | Calculated value |
|---|---|
| Other leg | 4 cm |
| Hypotenuse | 5 cm |
| Area | 6 cm² |
| Perimeter | 12 cm |
| Angle opposite leg a | 36.869898° |
Adjacent leg and acute angle
Given: Adjacent leg b = 4; Acute angle θ = 36.86989765.
a = b tan θ
| Measurement | Calculated value |
|---|---|
| Hypotenuse | 5 cm |
| Area | 6 cm² |
| Perimeter | 12 cm |
| Angle opposite leg a | 36.869898° |
Hypotenuse and acute angle
Given: Hypotenuse c = 5; Acute angle θ = 36.86989765.
a = c sin θ; b = c cos θ
| Measurement | Calculated value |
|---|---|
| Hypotenuse | 5 cm |
| Area | 6 cm² |
| Perimeter | 12 cm |
| Angle opposite leg a | 36.869898° |
Check the answer’s dimensions
An area contains a product of two lengths, while volume contains three. A perimeter or radius is still a length. If your input measurements are mixed between metres and centimetres, convert them to a common unit first. A realistic-looking number can still be wrong if the units were inconsistent.